DRAINING
| WARNING | Do not remove cylinder block drain plugs or loosen radiator draincock with system hot and under pressure. Serious burns from coolant can occur. |
Note. Typical drain plug shown in illustration.
DO NOT WASTE reusable coolant. If solution is clean, drain coolant into a clean container for reuse.
- Remove radiator pressure cap.
- Raise and secure vehicle.
- If equipped, remove the underbody splash shield.
- Loosen radiator petcock.
- Drain coolant into a clean container.
- If necessary, to perform a complete coolant drain of the engine, remove the drain plug (1) from the engine block.
REVERSE FLUSHING
Reverse flushing of cooling system is the forcing of water through the cooling system. This is done using air pressure in the opposite direction of normal coolant flow. It is usually only necessary with very dirty systems with evidence of partial plugging.
REVERSE FLUSHING RADIATOR
Disconnect radiator hoses from radiator inlet and outlet. Attach a section of radiator hose to radiator bottom outlet fitting and insert flushing gun. Connect a water supply hose and air supply hose to flushing gun.
| CAUTION | Internal radiator pressure must not exceed 138 kPa (20 psi) as damage to radiator may result. |
Allow radiator to fill with water. When radiator is filled, apply air in short blasts. Allow radiator to refill between blasts. Continue this reverse flushing until clean water flows out through rear of radiator cooling tube passages. Have radiator cleaned more extensively by a radiator repair shop.
REVERSE FLUSHING ENGINE
Drain cooling system. Remove thermostat housing and thermostat. Install thermostat housing. Disconnect radiator upper hose from radiator and attach flushing gun to hose. Disconnect radiator lower hose from water pump and attach a lead-away hose to water pump inlet fitting.
| CAUTION | On vehicles equipped with a heater water control valve, be sure heater control valve is closed (heat off). This will prevent coolant flow with scale and other deposits from entering heater core. |
Connect water supply hose and air supply hose to flushing gun. Allow engine to fill with water. When engine is filled, apply air in short blasts, allowing system to fill between air blasts. Continue until clean water flows through the lead away hose.
Remove lead away hose, flushing gun, water supply hose and air supply hose. Remove thermostat housing and install thermostat. Install thermostat housing with a replacement gasket. Refer to Thermostat Replacement. Connect radiator hoses. Refill cooling system with correct antifreeze/water mixture. Refer to Refilling the Cooling System.